From d24cefd0553ea2f1fb96f4ff9cee04f21cbc6713 Mon Sep 17 00:00:00 2001
From: Hadi Moshayedi <hadi@moshayedi.net>
Date: Wed, 18 Sep 2019 18:39:23 -0700
Subject: [PATCH] Set active snapshot before SyncMetadataToNodes().

---
 src/backend/distributed/utils/maintenanced.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/backend/distributed/utils/maintenanced.c b/src/backend/distributed/utils/maintenanced.c
index 6f274daa9..9b640c5d7 100644
--- a/src/backend/distributed/utils/maintenanced.c
+++ b/src/backend/distributed/utils/maintenanced.c
@@ -375,6 +375,12 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 			InvalidateMetadataSystemCache();
 			StartTransactionCommand();
 
+			/*
+			 * Some functions in ruleutils.c, which we use to get the DDL for
+			 * metadata propagation, require an active snapshot.
+			 */
+			PushActiveSnapshot(GetTransactionSnapshot());
+
 			if (!LockCitusExtension())
 			{
 				ereport(DEBUG1, (errmsg("could not lock the citus extension, "
@@ -386,6 +392,7 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 				Async_Notify(METADATA_SYNC_CHANNEL, NULL);
 			}
 
+			PopActiveSnapshot();
 			CommitTransactionCommand();
 			ProcessCompletedNotifies();